Hi, Nick. As you’re probably already aware, all Digital Audio Workstation (DAW) software programs feature a “piano roll” view which is pretty nifty and allows for more control than entering notes on staffs, and of course allows for playback on a MIDI keyboard. A great way to experiment with this is by downloading and installing Cakewalk by Band Lab, which is free software which used to be known as Sonar Platinum and sold for about $400. I suspect, though, that what you are suggesting is using a tracker bar mechanism and actual player piano rolls to play through a MIDI keyboard. That would certainly be feasible, but the cost could be somewhat high. I used to rebuild player pianos for a living, and found that one of the best places to find player piano mechanisms on the cheap was at old churches. That’s because when a player piano stopped working, most owners either sold the piano cheaply, or gave it to a church, because the cost to rebuild the mechanism was prohibitive. I was up inside a bell tower of a church and actually found two player piano mechanisms that had been stored there. In looking around the church, I also found the two pianos they had been removed from, so I proposed a deal wherein I would take the pianos and the player mechanisms in exchange for tuning and repairing another piano which they had but were unable to use because some demented prankster had snapped off all 88 of the piano hammers. Another good place to look for a player piano mechanism is Facebook Marketplace, where you can probably find an old player piano that’s cheap, or even free for the taking. Chances are pretty good that you would need to restore the mechanism so that it is functional, but that isn’t difficult and the materials needed are fairly inexpensive. Aside from the player mechanism, you will also need a vacuum source. Older player pianos had foot pumped pedals which operated bellows to provide the vacuum, but you could use an electric vacuum pump made for player piano conversions, or even a vacuum cleaner for that matter. Once you have the mechanism functioning, you would need to convert the mechanical actions, which would ordinarily activate piano keys, into digital signals that would feed to the MIDI keyboard via a standard or USB MIDI cable. Another option, when using a player piano mechanism, would be to entirely remove or bypass the key activating mechanisms, which are basically operated by pneumatic pouches connected to the tracker bar by rubber tubing. You could, for example, insert fiberoptic strands through each of the tubes, placing one end very close to the tracker bar, and the opposite end could be used to activate a photocell or photoresistor to complete a circuit. An LED light bar shining on the roll paper as it moves across the tracker bar would activate each fiberoptic strand when its corresponding slot opens in the paper roll. This would of course eliminate the need of rebuilding the entire mechanism, although replacing the rubber tubing would be advised.
